function diff = delta_OJS_p(m,param)
    % derivative of delta(m) under C=0 in hiring region

    delta_1 = (param.r +param.zeta + param.s.*param.lambda + param.omega_0./param.c).*param.m_h^(-1./(1-param.alpha)) ...
        - (1-param.omega_1)./param.alpha./param.c.*param.m_h^(1-1./(1-param.alpha));

    diff=(1-param.omega_1)./param.alpha./param.c ...
        + delta_1.*m.^(1/(1-param.alpha))./m.*1/(1-param.alpha);


end 